Showthat the algorithm for concurrently accessing a B+tree in which operations that only search the tree use lock coupling and operations that modify the tree handle write latches in a two-phase fashion guarantees that all operations are carried out successfully.
What will be an ideal response?
Since modifying operations use two-phase locking and searches do not modify the
tree, modifying operations are serializable. Furthermore, since searches are read-only,
they too are serializable. Hence, our only concern is that a modifying operation does
not serialize with a search. Consider the interaction of a search, S, and a modifying
operation, M. If M starts at the root first, S will have to wait until M completes before
it starts, so they are serializable. Suppose S starts at the root first. Lock coupling
guarantees that S never releases a latch until it acquires the next latch on the search
path. Hence, it always holds a latch and as a result, is always at least one step ahead
of M. As a result, in any read/write conflict between operations of S and M, S always
precedes M and hence S and M are serializable.
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Which of the following statements is false?
a = [[77, 68, 86, 73], [96, 87, 89, 81], [70, 90, 86, 81]]a. Writing the list as follows makes its row and column tabular structure clearer: a = [77, 68, 86, 73], # first student's grades [96, 87, 89, 81], # second student's grades [70, 90, 86, 81] # third student's grades b. The element names in the last column all have 3 as the second index. c. The following nested for statement outputs the rows of the two-dimensional list a one row at a time: for row in a: for item in row: print(item, end=' ') print() d. All of the above statements are true.
What are the advantages of using onscreen windows?
What will be an ideal response?
________ is software that manages information about customers, including contact information, purchases, and needs
A) CRM B) SCM C) SFA D) BPR
An organization notices a large amount of malware and virus incidents at one satellite office, but hardly any at another. All users at both sites are running the same company image and receive the same group policies. Which of the following has MOST likely been implemented at the site with the fewest security issues?
A. Consent to monitoring B. Business continuity measures C. Vulnerability scanning D. End-user awareness training